(Reuters) - A South Korean activist group led by a defector from North said on Tuesday it had launched balloons with messages critical of the North's leader across the border, defying a request by Seoul to refrain as it pursues dialogue with Pyongyang.

The message launch comes after South Korean President Park Geun-hye renewed calls for dialogue with North Korea last week and asked her government on Monday to create a political environment that would help the North come forward to talks.

Pyongyang had threatened military action if the leaflet launches were allowed by South Korean authorities and said the protest balloons were damaging the chances of inter-Korean dialogue.

Park Sang-hak, the North Korean defector who has previously launched message balloons into the North, said his group late on Monday had secretly sent about 100,000 leaflets.

He said at a news conference that if Pyongyang did not respond to the South's call for a meeting by Feb. 18, his group would send a massive number of DVD and USB (memory sticks) copies of the film 'The Interview' to the North.

The movie features a fictional plot to assassinate North Korean leader Kim Jong Un. The North has said Washington has committed "an act of war" by allowing the movie to be made.

The North has previously fired at the protest balloons near the border with shells landing in the South.

The leaflets often single out the North's young leader Kim Jong Un, questioning his legitimacy to rule a country where people struggle with poverty while his family lives in luxury and scarce resources are channeled to arms programs.